1. Field of the Invention
The invention relates to a consolidated duplex heat exchanger, and more particularly relates to a heat exchanger comprising different kinds of unit heat exchangers such as an engine cooling radiator and an air-conditioning condenser in automobiles wherein the unit heat exchangers are arranged parallel and consolidated into the duplex heat exchanger.
2. Description of the Prior Art
Heat exchangers for automobiles are recently required to be more compact in order to reduce the space for installation on one hand, and also to decrease works for assembling the heat exchangers on the other hand. Therefore, a pair of unit heat exchangers of different kinds are often combined to form a consolidated duplex heat exchanger in a case where the unit heat exchangers are arranged close together. Examples of such combinations of unit heat exchangers include a pair of a radiator for engine and a condenser for car cooler, a pair of a heater core and an evaporator, and a pair of the radiator and an intercooler.
One type of such consolidated heat exchangers is already disclosed in the Japanese Patent Publication Kokai 1-247990. This heat exchanger had a basic configuration as shown in FIGS. 6 and 7 wherein a second unit heat exchanger 20 constituting for instance a condenser for car cooler is installed in parallel with and in front of a first unit heat exchanger 10 constituting a radiator. These unit heat exchangers are consolidated into one duplex heat exchanger. The first unit heat exchanger has a structure such that a number of flat tubes 13 are arranged parallel with each other and connected to an upper and lower header tanks 11 and 12 in fluid communication therewith. Corrugated fins 14 are interposed between one such flat tube and the next. Similarly, the second unit heat exchanger 20 is so constructed that a number of parallel flat tubes 23 are connected at their opposite ends to an upper and lower header tubes 21 and 22, respectively, with corrugated fins 24 interposed between one such flat tube and the next.
In the above-mentioned consolidated heat exchanger, it is already proposed that, as disclosed in the abovenoted Japanese Patent Publication and shown in FIG. 8, the first and second unit heat exchangers may own the same corrugated fins jointly so as to simplify the assembling process and improve the strength of connection between the two unit heat exchangers. Opposite ends of each corrugated fin are respectively connected to the unit heat exchangers.
However, the prior art consolidated heat exchanger comprising the common corrugated fins will inevitably cause thermal interference due to the continuous common fins 14 and 24 extending between the first and second unit heat exchangers 10 and 20. If the unit heat exchangers work at different temperatures, then heat from one unit heat exchanger working at a higher temperature will affect the other unit heat exchanger working at a lower temperature to thereby reduce its efficiency of heat exchange.
It will thus be necessary to increase the distance between the unit heat exchangers 10 and 20 to a satisfactory degree in order to minimize such a thermal interference. This will bring about a serious problem that the greater the distance is, the less compact would be the consolidated heat exchanger against its expected task.